1. Technical Field
The present invention relates to a semiconductor device manufacturing method, a semiconductor device, a laminated semiconductor device, a circuit substrate, and an electronic apparatus.
2. Related Art
Recently, along with demands to reduce the size and weight of portable electronic apparatuses such as mobile telephones, note-type personal computers, and personal data assistants (PDAs), attempts are also being made to reduce the size of various electronic components, such as semiconductor devices, which are installed inside these electronic apparatuses. Accordingly, a three-dimensional mounting technique for semiconductor devices is proposed. Three-dimensional mounting is a technique of laminating semiconductor devices which have similar or different functions.
A semiconductor device for three-dimensional mounting should preferably by small and thin. A thin semiconductor device may for example be manufactured by the following method. A semiconductor wafer having a plurality of semiconductor devices disposed thereon is diced to a midway point, and the faces of the diced semiconductor wafer are covered with resin. The wafer is thinned by backgrinding and the thin semiconductor wafer is transferred to a dicing tape. After transferal to the dicing tape, it is separated into individual semiconductor devices (e.g., see Japanese Unexamined Patent Application, First Publication No. 2001-127206).
In this method, the thinness of the semiconductor wafer makes it liable to break, consequently making it difficult to handle when separating it into individual semiconductor devices e.g., when transferring the semiconductor wafer to the dicing tape.
There is another three-dimensional mounting technique of laminating a plurality of semiconductor devices, each having a semiconductor element whose two faces are covered with an insulating film and a penetrating electrode which penetrates through the semiconductor element, on top of each other (e.g., see Japanese Unexamined Patent Application, First Publication No. 2001-277689).
A semiconductor device with a penetrating electrode structure has lower strength (e.g., transverse rupture strength) than one which does not have such a structure, since a through-hole for forming the penetrating electrode can cause the semiconductor device to break. In particular, chips, cracks, and the like, in the semiconductor element are caused by dicing when a plurality of semiconductor devices on a semiconductor wafer are separated into individual devices. The chips reduce the strength of the semiconductor element, and the cracks spread toward the through-hole, making the semiconductor element liable to break. In other words, a semiconductor device which includes a penetrating electrode has a problem of low strength.
One technique for increasing the strength of the semiconductor device is to cover all the faces of the semiconductor element with a layer of resin (e.g., see Japanese Unexamined Patent Application, First Publication No. 2001-244281).
However, when all the faces of the semiconductor element are covered with an insulating film, it is difficult to strictly control the thickness of the insulating film. If the thickness of the insulating film is uneven, differences in the film stress may cause the semiconductor element to warp. This reduces the reliability of the semiconductor device.